Make peeking back into the stack work for back traces

GCC 10 doesn't like peeking back before the end of an arrary (which
is used to peek into the stack).  Fix this.

https://github.com/vmware/open-vm-tools/issues/429

diff --git a/open-vm-tools/lib/user/utilBacktrace.c b/open-vm-tools/lib/user/utilBacktrace.c
index 99871365647512953e9ab9ae8de1d3f41e356cfa..d26d21e7dc8116bbd262ae9a7cfb572ad94094f4 100644 (file)
--- a/open-vm-tools/lib/user/utilBacktrace.c
+++ b/open-vm-tools/lib/user/utilBacktrace.c
@@ -343,7 +343,8 @@ UtilBacktraceFromPointerWithFunc(uintptr_t *basePtr,       // IN:
                                i, x[0], x[1], dli.dli_sname, dli.dli_fname,
                                 dli.dli_fbase);
       } else {
-         outFunc(outFuncData, "SymBacktrace[%d] %#08x eip %#08x \n", i, x[0], x[1]);
+         outFunc(outFuncData, "SymBacktrace[%d] %#08x eip %#08x \n", i, x[0],
+                 x[1]);
       }
       x = (uintptr_t *) x[0];
    }
@@ -394,6 +395,7 @@ Util_Backtrace(int bugNr) // IN
  *-----------------------------------------------------------------------------
  */
 
+
 void
 Util_BacktraceWithFunc(int bugNr,                // IN:
                        Util_OutputFunc outFunc,  // IN:
@@ -413,7 +415,7 @@ Util_BacktraceWithFunc(int bugNr,                // IN:
    if (bugNr == 0) {
       outFunc(outFuncData, "Backtrace:\n");
    } else {
-      outFunc(outFuncData, "Backtrace for bugNr=%d\n",bugNr);
+      outFunc(outFuncData, "Backtrace for bugNr=%d\n", bugNr);
    }
    frames = backtrace(callstack, ARRAYSIZE(callstack));
    for (i = 0; i < frames; i++) {
@@ -431,14 +433,14 @@ Util_BacktraceWithFunc(int bugNr,                // IN:
       }
    }
 #else
-   uintptr_t *x = (uintptr_t *) &bugNr;
-
    if (bugNr == 0) {
       outFunc(outFuncData, "Backtrace:\n");
    } else {
-      outFunc(outFuncData, "Backtrace for bugNr=%d\n",bugNr);
+      outFunc(outFuncData, "Backtrace for bugNr=%d\n", bugNr);
    }
-   /* coverity[ptr_arith] */
-   UtilBacktraceFromPointerWithFunc(&x[-2], outFunc, outFuncData);
+
+   UtilBacktraceFromPointerWithFunc(__builtin_frame_address(0), outFunc,
+                                    outFuncData);
 #endif
 }
+